An audio/video information system for recording and playing back audio/video information has been described in U.S. Pat. Nos. 3,842,194, 3,842,217 and 3,909,517 to Clemens. According to this system, audio and video information and recorded in the form of geometric variations in spiral grooves on the surface of a disc. Disc replicas are then made of an insulating material such as vinyl and are coated first with a conductive film, then with a dielectric film and finally with a lubricant layer. A metallized stylus is utilized as a second electrode forming a capacitor with the video disc. The audio/video information is monitored by the stylus which detects changes in capacitance between the stylus and the video disc as the geometric variations in the form of depressions pass under the stylus.
In the above mentioned copending application to Priestley et al a silicon oxide dielectric layer is deposited on a substrate by evacuating a chamber and introducing into said chamber the substrate, oxygen and a dielectric precursor which has the formula ##STR2## wherein R.sub.1 is selected from the group consisting of H or --CH.sub.3, R.sub.2 and R.sub.3 are independently selected from the group consisting of H, --CH.sub.3, --OCH.sub.3, or --OC.sub.2 H.sub.5 and R.sub.4 is selected from the group consisting of --OCH.sub.3 or --OC.sub.2 H.sub.5. The silicon oxide dielectric layer is deposited onto the conductive surface by activating the precursor around the substrate by means of a glow discharge. The silicon oxide dielectric layers are deposited at high rates with low dielectric precursor pressures in the deposition chamber and the deposited silicon oxide layers do not cause excess wear of either the disc or stylus upon playback.
It has been sought, however, to deposit silicon oxide layers at even higher deposition rates at low dielectric precursor pressures.